PT-2026-39217 · Grimmory · Grimmory

Acfirthh · Published 2026-05-08 · Updated 2026-05-09 · CVE-2026-42451

Positive Technologies (AI Summary)

CVSS v3.1

6.3

Medium

Base vector

AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L

Name of the Vulnerable Software and Affected Versions Grimmory versions prior to 2.3.1

Description A stored cross-site scripting (XSS) issue in the browser-based EPUB reader allows an attacker to embed arbitrary JavaScript within a crafted EPUB file. When a user opens the affected book, the script executes in the browser with full access to the application's session context. This can lead to session token theft and account takeover, including administrative access if an administrator opens the file.

Recommendations Update to version 2.3.1.

Fix

XSS

Weakness Enumeration

CWE-79

CWE-80

Related Identifiers

CVE-2026-42451

Affected Products

Grimmory

References · 6

• https://nvd.nist.gov/vuln/detail/CVE-2026-42451 · Security Note
• https://github.com/grimmory-tools/grimmory/security/advisories/GHSA-frv6-5wq5-9p24 · Note
• http://github.com/grimmory-tools/grimmory/releases/tag/v2.3.1 · Note
• https://twitter.com/CVEnew/status/2053131408668074246 · Twitter Post
• https://t.me/CVEtracker/53176 · Telegram Post
• https://twitter.com/VulmonFeeds/status/2052921960183582767 · Twitter Post